A travelling mold for the manufacturing of ribbed pipe and the like uses mold block sections having a sophisticated construction required for the accurate formation of the pipe. Specific pipe grooves must be provided in the mold block sections to shape the ribbing on the pipe and air channels must be provided in order to move the plastic material forming the pipe through either positive or negative pressure into the grooves.
As a result of the detailing required in the mold block sections, they are expensive to manufacture. Furthermore, a conventional travelling mold requires an endless chain of side by side mold block sections completely around the mold.
There are benefits to increasing the size of a travelling mold. For example, a longer travelling mold has a longer molding tunnel enabling higher pipe production. In addition, extending the length of the mold also increases the mold base producing a steadier mold. However, from a negative standpoint, when working with a conventional mold, there is a substantial cost increase incurred for the additional mold block sections required as a result of the increased length of the mold.